1. Field of the Invention
The present invention relates to a sealing apparatus comprising at least one o-ring and a groove capable of retaining the o-ring and secondary sealing rings or grounding gaskets adjacent to the o-ring.
2. Discussion of the Background
In many hardware configurations, maintaining a seal between components is an important design consideration. For example, in plasma processing at low pressure, the connection of various parts to form a vacuum-tight process chamber requires sealing members to maintain the vacuum integrity at these connections.
Typically, a sealing member can comprise a simple o-ring configuration. Generally, where two connecting parts meet, each part is equipped with a surface that cooperates with the surface of the other part in a known way. At least one of these surfaces includes a sealing member. The sealing member typically includes an o-ring, secured within a groove. Where conductive parts are connected, the connection between these parts also requires a grounding gasket to act as a circuit bridge. The grounding gasket also requires a groove.
As illustrated in FIG. 1 for the connection of two cylindrical components, these grooves 5, 3 are substantially circular, centered about a center of the surface, and contained within the surfaces of at least one of the mating parts 1. As shown in FIG. 2, the groove 5 securing the o-ring 6 can comprise a dovetail or a rectangular cross section. As such, the groove 5 will be narrower where the groove is coplanar with the mating surface 1A. Therefore, dovetail grooves have the advantages of being able to secure an o-ring inside, while allowing an upper portion of the o-ring to protrude out of the groove and contact the surface of another mating part and allowing the o-ring to spread out within the groove under compression.
Thus, when the mating parts are brought together, a seal of an interior region between the parts from an exterior region is formed where the o-ring 6 contacts the surfaces of the groove and the second mating part. Where an electrical connection must be maintained between the parts, it is known to use a grounding gasket 4. The grounding gasket 4 contacts both mating parts as the o-ring 6 is compressed, acting as a circuit bridge and electrically coupling both parts. In general, a separate groove 3, 5 is formed for each o-ring 6 and each grounding gasket 4, respectively.
However, the use of known dovetail grooves also usually requires a groove relief in order to be able to extract the o-ring. A groove relief is a discontinuity in the groove at a particular point, and appears wider than the rest of the groove. Without the groove relief 7, removal of the o-ring is more difficult. In fact, the removal of the o-ring 6 from groove 5 without the groove relief 7 can cause damage to the o-ring 6 and/or the groove 5 that may disrupt the vacuum integrity of the mated components.
Moreover, removal of an o-ring in a groove 5 having a groove relief 7 requires that a narrow prying tool be inserted into the groove relief 7. An applied torque then forces a portion of the o-ring 6 out of position. Once a portion of the o-ring 6 is out of position, the remainder can be forcefully pulled out of the groove 5.
Ultimately, repeatedly prying o-rings 6 out of grooves 5 in mating surfaces is a harmful practice since the prying action leads to the wear and tear of the various parts. Additionally, the manufacture of groove reliefs increases labor and machining costs and is not always chosen. For mating surfaces requiring multiple seals and/or mating surfaces requiring seals and additional grooves for grounding gaskets, the need for extra grooves and groove reliefs creates a need for the mating surfaces to be larger, thus leading to increases in materials costs.